This is the exact package, I used to upgrade from 3.41, using a dongle, to CFW. 3.55.

This is a simple guide for the noobs lol :-)

- Delete all game data (not save game data)

- Upgrade to official firmware 3.55 (Regardless of which firmare you are currently on)
Copy 'ps3' folder from 'step one' to root of USB Stick. Insert USB into PS3 and update through XMB (or recovery mode if the system tells you that you already have the latest update)

- Install Custom Firmware

Copy 'ps3' folder from 'step 2' to root of USB Stick (remember to remove folder from step 1 on USB).Insert USB into PS3 and update through XMB (or recovery mode if the system tells you that you already have the latest update.)